HELP NEEDED! My wife's 5c won't recognise on my laptop anymore. I plug it in and the laptop makes a sound but won't show up the phone. I only recently discovered this problem when I upgraded. It will recognise my 5c and even the iPad but not her 5c

I discovered this problem when I upgraded my iPhone 4 to a 5c.

My laptop will recognise my 5c and even the wife's iPad but won't recognuse her 5c, when I plug it in it makes a sound but just doesn't show up in iTunes.

It DID work on my laptop as recently as November when I backed up her phone and updated her software but like I say ever since I upgraded it just won't recognise her 5c but does mine.

I just can't think what is wrong? I haven't messed around with anything on the laptop or messed around with the wife's settings on her 5c

HELP!!!!